Human reliability analysis: A critique and review for managers

In running our increasingly complex business systems, formal risk analyses andrisk management techniques are becoming a more important part of a manager'stool-kit. Moreover, it is also becoming apparent that human behaviour is often aroot or significant contributing cause of system failure. This latterobservation is not novel; for more than 30 years it has been recognised that therole of human operations in safety critical systems is so important that theyshould be explicitly modelled as part of the risk assessment of plantoperations. This has led to the development of a range of methods under thegeneral heading of human reliability analysis (HRA) to account for the effectsof human error in risk and reliability analysis. The modelling approaches usedin HRA, however, tend to be focussed on easily describable sequential, generallylow-level tasks, which are not the main source of systemic errors. Moreover,they focus on errors rather than the effects of all forms of human behaviour. Inthis paper we review and discuss HRA methodologies, arguing that there is a needfor considerable further research and development before they meet the needs ofmodern risk and reliability analyses and are able to provide managers with theguidance they need to manage complex systems safely. We provide some suggestionsfor how work in this area should develop.